1. Field of the Invention
This invention relates to a plasma display panel, and more particularly to a method and an apparatus for driving a plasma display panel that is adaptive for improving brightness as well as realizing a high resolution.
2. Description of the Related Art
Generally, a plasma display panel (PDP) radiates a phosphorus by an ultraviolet generated during a discharge of He+Xe, Ne+Xe or He+Ne+Xe gas to thereby display a picture including characters and graphics. Such a PDP is easy to be made into a thin-film and large-dimension type. Moreover, the PDP provides a very improved picture quality owing to a recent technical development. Particularly, a three-electrode, alternating current (AC) surface-discharge type PDP has advantages of a low-voltage driving and a long life because it can lower a voltage required for a discharge using wall charges accumulated on the surface thereof during the discharge and protect the electrodes from a sputtering caused by the discharge. Further, since the PDP does not need to form an active switching device for each cell like a liquid crystal display LCD, its fabricating process is simple, it is advantageous to be made into a big screen and its response speed is fast.
Referring to FIG. 1, a discharge cell of a three electrode AC discharge PDP includes a scanning electrode 30Y and a sustaining electrode 30Z formed on an upper substrate 10, and an address electrode 20X formed on a lower substrate 18.
The scanning electrode 30Y and the sustaining electrode 30Z include transparent electrodes 12Y and 12Z and metal bus electrodes 13Y and 13Z formed on one side edge of the transparent electrode with their line width narrower than that of the transparent electrode 12Y and 12Z. The transparent electrodes 12Y and 12Z are generally formed from Indium-Tin-Oxide ITO on the upper substrate 10. Chromium Cr/Copper Cu/Chromium Cr are deposited by a deposition method, and then an Etching process is carried out to form the metal bus electrode, or that is formed by printing photosensitive Silver Ag paste, then patterning it, and then firing it. There are an upper dielectric layer 14 and a passivation film 16 deposited on the upper substrate 10 provided with the scanning electrode 30Y and the sustaining electrode 30Z. In the upper dielectric layer 14, wall charges generated upon a plasma discharge are accumulated. The passivation film 16 protects the upper dielectric layer 14 from a sputtering caused upon the plasma discharge and increase an emission efficiency of secondary electrons. Normally, the passivation film 16 is made from Magnesium Oxide MgO. The address electrode 20X are formed in a direction of intersecting the scanning electrode 30Y and the sustaining electrode 30Z. There are a lower dielectric layer 22 and barrier ribs 24 formed on a lower substrate 18 provided with the address electrode 20X. There is a phosphorus layer 26 formed on the surface of the barrier ribs and the lower dielectric layer 22. The barrier ribs are formed in parallel to the address electrode 20X to divide discharge cells physically and to prevent UV ray and visible ray generated by the discharge from leaking to adjacent discharge cells The phosphorus layer 26 is excited by the UV ray generated upon the plasma discharge and radiates to generate any one visible ray among red, green and blue. There is inactive mixture gas such as He+Xe, Ne+Xe or He+Ne+Xe for the discharge interposed in a discharge space of the discharge cell provided between the upper/lower substrates 10 and 18 and the barrier ribs 24.
The arrangement of the electrodes of the PDP is shown as in FIG. 2. As can be seen in FIG. 2, the scanning electrode Y1 to Yn and the sustaining electrode line Z are parallel and form a pair in one discharge cell. The address electrode line X1 to Xm intersects a pair of sustaining electrode lines Y1 to Yn, Z. Accordingly, one pair of sustaining electrode lines Y1 to Yn, Z and one address electrode line X1 to Xm cross each other in one discharge cell. One pixel 200 is arranged side by side in a horizontal direction and includes three discharge cells 100, which displays red, green and blue respectively.
Such a PDP divides a time period of one field of a video signal into several sub-fields SF1 to SF8, which have their emission frequency different from one another, to display a video. Each sub-field is divided again into a reset period for generating a discharge uniformly, an address period A1 to A8 for selecting discharge cells and a sustaining period S1 to S8 for realizing gray level in accordance with a discharge frequency. The reset period and the address period of each sub-field are the same every sub-field, whereas a sustaining period and the discharge frequency thereof increase proportional to 2n (provided n=0,1,2,3,4,5,6,7) in each sub-field. Like this, since the sustaining periods are different in each sub-field, it is possible to realize a gray level of video.
In order to increase a display quality of the PDP, PDP manufacturers have actively been studying on a discharge cell structure and a new driving method for realizing a high resolution and a high speed driving.
FIG. 4 briefly illustrates a conventional PDD which is scanned in a interlaced scanning;
Referring to FIG. 4, in the conventional PDP scanned in the interlaced scanning, the scanning electrode lines Y1, Y2 and Y3 and the sustaining electrode lines Z1, Z2 and Z3 are shared by two discharge cells perpendicularly adjacent thereto, and odd horizontal display lines HLodd1, HLodd2 and HLodd3 are separately displayed from even horizontal display lines HLeven1, HLeven2 and Hleven3.
Further, the PDP, as in FIG. 4, includes the barrier ribs 24 of a stripe shape. Since the PDP has the barrier ribs formed in parallel, it is advantageous that fabrication is easy and space charges freely move between discharge cells. However, since there is no barrier rib between perpendicularly adjacent discharge cells, there is a problem of cross talk being generated between the discharge cells.
In order to solve the problem caused in the PDP structure of FIG. 4, a PDP proposed in Japanese Laid-open Patent Gazette No. 2001-176396, as in FIG. 5, has extended parts and narrow parts repeated perpendicularly and includes barrier ribs 54 formed in a lattice shape.
In the PDP as in FIG. 5, scanning electrode lines Y1 to Y5 and sustaining electrode lines Z1 to Z4 are shared by discharge cells adjacent perpendicularly. Also, in the PDP driving method as in FIG. 5 according to U.S. Pat. No. 6,281,628, one pixel P includes three sub-pixels of red, green and blue together with two scanning electrode lines Y1 and Y2, one sustaining electrode line Z1 and three address electrode lines X3, X4 and X5, and each of sub-pixels of the pixel P is selected by an address discharge and displays a picture by a sustaining discharge.
A PDP shown in FIG. 6 has barrier ribs 64 formed in a lattice shape similarly to that in FIG. 5, but there is a difference in the fact that each of discharge cells is separately composed of scanning electrode lines Y1 to Y8 and sustaining electrode line Z1 to z8 which are adjacent thereto perpendicularly. Accordingly, in the PDP of FIG. 6, one pixel P includes three sub-pixels of red, green and blue together with two scanning electrode lines Y1 and Y2, two sustaining electrode lines Z1 and Z2 and three address electrode lines X3, X4 and X5, and each of sub-pixels of the pixel P is selected by an address discharge and displays a picture by a sustaining discharge.
In the PDP of FIGS. 5 and 6, the pixel P is formed in a ‘Δ’ (delta) type. The PDP of such a delta type pixel structure, as can be seen in FIG. 7, has only four horizontal display lines carry out actual display among eight rows of discharge cells (i−4 to i+3). In other words, the pixels P arranged perpendicularly along the (j−2)th address electrode line are only four of P(i−3½, j−2), P(i−1½, j−2), P(i+1½, j−2) and P(i+2½, j−2) among eight rows of discharge cells (i−4 to i+3). Also, the pixels P arranged perpendicularly along the (j+1)th address electrode line are only four of P(i−3½, j+1), P(i−1½, j+1), P(i+1½, j+1) and P(i+2½, and P(i+2½, j+1) among eight rows of discharge cells (i−4 to i+3).
Accordingly, it is difficult to realize a PDP with high resolution and high definition in the PDP of the conventional delta type pixel structure. For example, according to the conventional delta type pixel structure, in order to realize a high resolution PDP with 760 or more horizontal lines, because the number of the discharge cell rows to be needed is twice as many, i.e., 1520, or more, so that it is inevitable that an overall size thereof get big. In order to solve this problem, the area of each discharge cell can be reduced, however if the area of each discharge cell gets small, here comes another problem that its brightness decrease as much.